The battery is an indispensable element of the generator and the electric motor vehicle. As the storage capacity of the battery deteriorates, the normal operations of the generator and the electric motor vehicle are adversely affected or even interrupted.
The battery set becomes an integral part of the operating system only after the battery set is initially charged such that the initial charge is followed by the discharge test, and that the discharge test is followed by the recharge. After a prolonged use of the battery, the storage capacity of the battery diminishes gradually due to the stripping off of the activated (effective) material or the hardening of the terminal plate. The reduction in the storage capacity of the battery results in an increase in the internal resistance of the battery. Such a circumstance as described above may happen to only one or two individual batteries of the whole set. In light of all batteries of the whole set being connected in series, one or two bad batteries can be the culprit of the reverse charge which transpires at the time when the battery set is discharged. As a result, the battery set is loaded and unable to furnish power. It is therefore imperative that the residual storage capacity and the residual characteristic of the battery set in operation must be monitored from time to time.
The conventional method for testing the battery storage capacity is based on the specific gravity measurement in place of the application of a dummy load to carry out the discharge experiment. The specific gravity measurement method can not be employed to test the storage capacity of those batteries which do not use water.
The inventor of the present invention has disclosed a method for testing the characteristics of a battery set. The method involves the use of a multiple loop voltage testing device by which the data of voltage and current of each individual battery of the battery set are collected and transmitted to a computer at the time when the battery set is charged and discharged. Upon completion of the charge testing and the discharge testing, the characteristics of the internal resistances of all batteries are computed by the computer on the basis of the terminal voltage of the batteries of the battery set. The internal resistance characteristics are then expressed by the curves. As a result, the comparison diagram of the characteristic curves is constructed. The characteristic of each battery of the battery set is judged by the interval between the two curves. This method is defective in design in that the comparison diagram contains numerous curves, which can cause a great deal of confusion unless the size scale is appropriately enlarged. In addition, this comparison approach is by no means revealing in view of the fact that it does not provide the residual capacity of each battery of the battery set in a quantitative term. In other words, this comparison approach serves to identify those batteries which are relatively poorer in characteristic. Moreover, the method is time-consuming such that the charge testing and the discharge testing take as long as 50 to 60 minutes.